One vertex per element, one color per generator, with an edge from x to x·s.
(3,7)(6,8)(9,10)(11,18)(12,16)(13,23)(14,24)(15,17)(19,22)(20,21)(25,26)(27,33)(28,29)(30,32)(31,35)(34,39)(36,40)(37,38) involution — undirected(1,2)(3,6)(4,5)(7,8)(11,12)(16,18)(19,21)(20,22)(25,27,31,30)(26,32,35,33)(28,36,39,38)(29,37,34,40)(2,5)(6,8)(9,11,15,12)(10,16,17,18)(13,21,24,19)(14,20,23,22)(25,27,31,30)(26,33,35,32)(28,36,39,38)(29,40,34,37)(9,12,15,11)(10,16,17,18)(13,21,24,19)(14,22,23,20)(25,28)(26,34)(27,36)(29,35)(30,38)(31,39)(32,40)(33,37)(1,2)(3,6)(4,5)(7,8)(9,13)(10,14)(11,19)(12,21)(15,24)(16,22)(17,23)(18,20)(25,29,31,34)(26,28,35,39)(27,37,30,40)(32,36,33,38)(1,3,4,7)(2,6,5,8)(9,14)(10,13)(11,20)(12,22)(15,23)(16,21)(17,24)(18,19)(25,30,31,27)(26,33,35,32)(28,38,39,36)(29,40,34,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.